The present invention relates to ophthalmic examination equipment and, more particularly, to an ophthalmic lighting apparatus for operable attachment to an ophthalmic article, such as an ophthalmic refractor, of the type which has an attachment element capable of supporting a reading card rod, and accordingly a reading card holder and reading card, so as to provide controlled and standardized illumination of at least a portion of the reading card during the ophthalmic examination.
Lighting devices used for illuminating reading cards of the type operably attached to ophthalmic articles such as ophthalmic refractors have been known in the art for many years. Many of such lighting devices are typically in the form of conventional multi-positionable lamps independently positioned and physically isolated from the ophthalmic article itself, which ophthalmic refractor, for example, utilizes a reading card assembly. The position and illumination of such independent light sources are, unfortunately, rarely maintained at a specific recommended illumination level, much less a predetermined, calibrated, distance away from the reading card during the actual ophthalmic examination. Accordingly, one of several problems associated with the use of such conventional independent lamps, is that the brightness of the light projected onto the reading card typically exceeds the ten to twenty foot candle illumination protocol recommended for an ophthalmic reading test. Accordingly, the results of the reading test may often be inconsistent, and in many cases, in error--with some patients complaining that their reading glasses "worked better" during examination than in use; due to over illumination of the reading test card. In addition, inasmuch as the lamps are not maintained in a predetermined, calibrated, orientation with respect to the reading card, the intensity of light projected onto the reading card may vary from examination to examination, with the wrong intensity of light otherwise recommended for such an examination being projected onto the reading card--thereby potentially resulting in an inaccurate diagnosis by the examiner.
It is accordingly not uncommon for an optometrist or ophthalmologist to prescribe corrective lenses to a patient, for reading, based upon the results of a reading examination given in association with a non-calibrated, non protocol-conforming conventional light projector, only to later find out that such lenses do not adequately correct the patients vision when he or she is attempting to read in a "real world" environment. Furthermore, inasmuch as many conventional style lamps are multi-positionable, and, accordingly, constantly re-adjusted (i.e. by swinging the lamp into proximate position for the examination, followed by making further manual adjustments thereto followed by raising the lamp and swinging it out of the way after the examination) breakage and/or other forms of malfunction of the lamp are not uncommon.
It is thus an object of the present invention to provide an ophthalmic lighting apparatus which is maintained at a predetermined, calibrated, position away from the reading card, so as to ensure that the industry recommended amount of light is being projected onto the reading card during every ophthalmic examination given.
It is also an object of the present invention to provide an ophthalmic lighting apparatus which is operably attached to a portion of an ophthalmic article, such as a reading card holder attached to an ophthalmic refractor, so that constant reorientation of the lighting apparatus, with respect to the reading card, is not required.
It is still further an object of the present invention to provide an ophthalmic lighting apparatus which includes a position sensitive switch which automatically results in the projection of light when the apparatus is in an ophthalmic examination position and automatically shuts of the light when the lighting apparatus is in a pre-ophthalmic examination position--while isolating wall current electrical conductors from contact with the metal refractor.
These and other objects of the present invention will become apparent in light of the present specification and drawings.